Special Issue - 2018 International Journal of Engineering Research & Technology (IJERT) ISSN: 2278-0181 Confcall - 2018 Conference Proceedings Satellite Communication with the Merge on Television Communication

Ayyasamy.T Deepika.S Keerthana. K Head of the Department UG Scholar UG Scholar Dept of Aeronautical Dept of Aeronautical Dept of Aeronautical Srinivasan Engineering College, Srinivasan Engineering College, Srinivasan Engineering College, Perambalur-621 212 Perambalur-621 212 Perambalur-621 212

Abstract - In the context of a worldwide communications with run-down batteries, and leftover rocket boosters all network, satellite communications systems are very important. contribute to the count. This online catalogs of satellite has Satellite communications links add capacity to existing almost 26,000 entries! communications capabilities and provide additional alternate Although anything that is in orbit around Earth is technically routings for communications traffic. Satellite links, as one of a satellite, the term "satellite" is typically used to describe a several kinds of long-distance links, interconnect switching centers located strategically around the world. They are part of useful object placed in orbit purposely to perform some the defense communication systems (DCS) network. One specific mission or task. We commonly hear about weather important aspect of the satellite communications network is that satellites, communication satellites and scientific satellite it continues in operation under conditions that sometimes render other methods of communications inoperable. Because of this, II. HELPFUL HINTS satellites make a significant contribution to improved reliability of Navy communications .When satellite television first hit the A.Types of Classification market in the early 1990s, home dishes were expensive metal • Weather satellites help meteorologists predict the units that took up a huge chunk of yard space. In these early weather or see what's happening at the moment. Typical years, only the most die-hard TV fans would go through all the hassle and expense of putting in their own dish. Satellite TV was weather satellites include the TIROS, COSMOS and GOES a lot harder to get than broadcast and CABLE AND TV. Today, satellites. you see compact satellite dishes perched on rooftops all over the • Communications satellites allow telephone and data United States. Drive through rural areas beyond the reach of the conversations to be relayed through the satellite. Typical cable companies, and you'll find dishes on just about every communications satellites include Telstar and Intelsat. house. The major satellite TV companies are luring in more • Broadcast satellites broadcast television signals from consumers every day with movies, sporting events and news one point to another (similar to communications satellites). from around the world and the promise of movie-quality picture • Scientific satellites perform a variety of scientific and sound. Satellite TV offers many solutions to broadcast and cable TV problems. Though satellite TV technology is still missions. The Hubble Space telescope is the most famous evolving, it has already become a popular choice for many TV scientific satellite, but there are many others looking at viewers. everything from sun spots to gamma rays. • Navigational satellites help ships and planes navigate. Keywords: Merge on television communication, satellite The most famous are the GPS NAVSTAR satellites. communication, GPS, encoding. • Rescue satellites respond to radio distress signals . • Earth observation satellites observe the planet for I. INTRODUCTION changes in everything from temperature to forestation to ice- sheet coverage. The most famous are the LANDSAT series. A satellite is basically any object that revolves around a planet in a circular or elliptical path. The moon is Earth's B.Satellite Television – A Merge original, natural satellite, and there are many manmade Satellite television really becomes important in (artificial) satellites, usually closer to Earth. areas where it is not possible to install cable and the broadcast • The path a satellite follows is an orbit. In the orbit, the television reception is poor. Both systems use radio wave farthest point from Earth is the apogee, and the nearest point signals to transmit and the waves travel in straight lines. That is the perigee. means for broadcast television, which is transmitted and • Artificial satellites generally are not mass-produced. Most received via land-based antenna, that the natural curvature of satellites are custom built to perform their intended functions. the earth will eventually break the signals' line of sight. It also Exceptions include the GPS satellites (with over 20 copies in means that other land based signals and obstructions are orbit) and the Iridium satellites (with over 60 copies in orbit). likely to interfere with the TV signal and cause some • Approximately 23,000 items of space junk-objects large distortion. Today, most satellite TV customers get their enough to track with radar that were inadvertently placed in programming through a direct broadcast satellite (DBS) orbit or have outlived their usefulness -- are floating above provider, such as DirecTV or DISH Network. The provider Earth. The actual number varies depending on which agency selects programs and broadcasts them to subscribers as a set is counting. Payloads that go into the wrong orbit, satellites package. Basically, the provider's goal is to bring dozens or

Volume 6, Issue 14 Published by, www.ijert.org 1 Special Issue - 2018 International Journal of Engineering Research & Technology (IJERT) ISSN: 2278-0181 Confcall - 2018 Conference Proceedings even hundreds of channels to your TV in a form that they're tiny squares of video data that make up the image you approximates the competition, cable TV. see. Unlike earlier programming, the provider's broadcast is completely digital which means it has much better picture and IV. ADVANTAGES OF SATELLITE sound quality. Early satellite television was broadcast in C- COMMUNICATION band radio -- radio in the 3.7-gigahertz (GHz) to 6.4-GHz frequency range. Digital broadcast satellite transmits Satellite links are unaffected by the propagation programming in the Ku frequency range (11.7 GHz to 14.5 variations that interfere with hf radio. They are also free from GHz ). the high attenuation of wire or cable facilities and are capable C.The Components of spanning long distances. The numerous repeater stations There are five major components involved in a direct to required for line-of-sight or tropo scatter links are no longer home (DTH) needed. They furnish the reliability and flexibility of service • Programming sources are simply the channels that provide that is needed to support a military operation. programming for broadcast. The provider doesn't create A.Capacity: original programming itself; it pays other companies (HBO, The present military communications satellite system is for example, or ESPN) for the right to broadcast their content capable of communications between backpack, airborne, and via satellite. In this way, the provider is kind of like a broker shipboard terminals. The system is capable of handling between you and the actual programming sources. (Cable TV thousands of communications channels. companies work on the same principle.) B.Reliability: • The broadcast center is the central hub of the system. Communications satellite frequencies are not dependent At the broadcast center, the TV provider receives signals upon reflection or refraction and are affected only slightly by from various programming sources and beams a broadcast atmospheric phenomena. The reliability of satellite signal to satellites in geosynchronous orbit. communications systems is limited only by the equipment • The satellites receive the signals from the broadcast reliability and the skill of operating and maintenance station and rebroadcast them to Earth. personnel. • The viewer's dish picks up the signal from the satellite C.Vulnerability: (or multiple satellites in the same part of the sky) and passes it Destruction of an orbiting vehicle by an enemy is on to the receiver in the viewer's house. possible. However, destruction of a single communications • The receiver processes the signal and passes it on to a satellite would be quite difficult and expensive. The cost standard TV. would be excessive compared to the tactical advantage gained. It would be particularly difficult to destroy an entire multiple-satellite system such as the twenty-six random-orbit III. ENCODING AND ENCRYPTION satellite system currently in use. The earth terminals offer a Encoding works in conjunction with compression to more attractive target for physical destruction. These can be analyze each video frame and eliminate redundant or protected by the same measures that are taken to protect other irrelevant data and extrapolate information from other frames. vital installations. A high degree of freedom from jamming This process reduces the overall size of the file. Each frame damage is provided by the highly directional antennas at the can be encoded in one of three ways: earth terminals. The wide bandwidth system that can • As an intraframe, which contains the complete image data accommodate sophisticated anti-jam modulation techniques for that frame? This method provides the least compression. also lessens vulnerability • As a predicted frame, which contains just enough D.Flexibility information to tell the satellite receiver how to display the Most operational military satellite earth terminals are frame based on the most recently displayed intraframe or housed in transportable vans. These can be loaded into cargo predicted frame. A predicted frame contains only data that planes and flown to remote areas. With trained crews these explains how the picture has changed from the previous terminals can be put into operation in a matter of hours. frame. Worldwide communications can be established quickly to • As a bidirectional frame, which displays information from remote areas nearly anywhere in the free world. the surrounding intraframe or predicted frames? Using data V. PROBLEMS AND SOLUTION from the closest surrounding frames, the receiver interpolates the position and color of each pixel. Conceptually, satellite TV is a lot like broadcast This process occasionally produces artifacts -- glitches in the TV. It's a wireless system for delivering television video image. One artifact is macro blocking, in which the programming directly to a viewer's house. Both broadcast fluid picture temporarily dissolves into blocks. Macro television and satellite stations transmit programming via a blocking is often mistakenly called pixilation, a technically radio signal. Broadcast stations use a powerful antenna to incorrect term which has been accepted as slang for this transmit radio waves to the surrounding area. Viewers can annoying artifact. Graphic artists and video editors use pick up the signal with a much smaller antenna. The main "pixilation" more accurately to refer to the distortion of an limitation of broadcast TV is range. The radio signals used to image. There really are pixels on your TV screen, but they're broadcast television shoot out from the broadcast antenna in a too small for your human eye to perceive them individually -- straight line. In order to receive these signals, you have to be

Volume 6, Issue 14 Published by, www.ijert.org 2 Special Issue - 2018 International Journal of Engineering Research & Technology (IJERT) ISSN: 2278-0181 Confcall - 2018 Conference Proceedings in the direct line of sight of the antenna. Small obstacles like trees or small buildings aren't a problem; but a big obstacle, such as the Earth, will reflect these radio waves. If the Earth were perfectly flat, you could pick up broadcast TV thousands of miles from the source. But because the planet is curved, it eventually breaks the signal's line of sight. The other problem with broadcast TV is that the signal is often distorted, even in the viewing area. To get a perfectly clear signal like you find on cable, you have to be pretty close to the broadcast antenna without too many obstacles in the way. satellite TV solves the problems of range and distortion by transmitting broadcast signals from satellites orbiting the Earth. Since satellites are high in the sky, there are a lot more customers in the line of sight. Satellite TV systems transmit and receive radio signals using specialized antennas called Fig.2 example of satellite communication satellite dishes.

REFERENCES

1. https://www.isro,gov.in/applications/satellite-communication 2. https://www.nasa,gov/directorates/heo/scan/communications/.../tx t_satellite_comm.htm 3. https://en.wikipedia.org/wiki/Communications_satellite 4. https://www.britannica.com/technology/satellite-communication 5. https://samm.univ- paris1.fr/IMG/doc/ieee_conference_paper_template.doc

Fig.1 model of satellite antenna

VI. ITS FUTURE USE In the future SATELLITE TV will open up so many possibilities that it is hard to imagine what our lives will be like in 30, or even just 20 years from now. To give an idea of how fast things are going. 50 years ago, there was nothing in space that was made by humans. Now there are even satellite graveyards (specific orbits where obsolete satellites are "parked"). The possibilities of satellite TV technology are growing faster every year. What took 10 years to develop 30 years ago is now done in 2 years; Satellite TV is one of the driving forces for satellite technologies because the need to please million of subscribers is much stronger than the need to please the relative limited needs of communications for commercial purposes. The future of satellite TV is so bright, that a supernova would pale in comparison.

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